Pitot assembly



: Nov. 16, 1965 H. s. TAYLOR ETAL 3,217,535

PITOT ASSEMBLY Filed Oct. 25, 1961 2 Sheets-Sheet l Nov. 16, 1965 TAYLORETAL 3,217,535

PITOT ASSEMBLY Filed Oct. 25, 1961 2 Sheets-Sheet 2 United States Patent3,217,535 PITOT ASSEMBLY Howard S. Taylor, Fox River Grove, and John G.Powers,

Wilmette, Ill., assignors to Airguide Instrument Company, a corporationof Illinois Filed Oct. 25, 1961, Ser. No. 147,607 12 Claims. (CL 73182)This invention relates to a Pitot assembly, or a velocity pressurepickup assembly, attachable to a boat as at the transom thereof forpicking up velocity pressure while the boat is in motion in water foractuating a pressure sensitive marine speedometer mechanism.

It is a general object of the invention to provide a new and improvedassembly of the type described.

Another object is to provide a new and improved Pitot assembly,including a bracket attachable to a boat as at the transom, a Pitot tubemounted on the bracket and adapted to extend into water when the boat isin motion for picking up velocity pressure, means supporting the tube onthe bracket for movement about an axis transverse to the tube so thatthe latter may yield on striking objects while the boat is in motion,and means resiliently urging the tube toward a normal, operativeposition.

A further object is to provide an assembly of the type mentioned,including means normally releasably locking the tube in the normal,operative position so that the tube will not yield merely by pressureexerted by the Water while the boat is in motion, but may yield uponimpact with an object in the water.

It is also an object of the invention to provide a Pitot assemblyincluding a mounting bracket, and a Pitot tube supported thereon, withmeans normally maintaining the Pitot tube in an operative position onthe bracket and resiliently yieldable to permit the tube to turn on thebracket laterally relative to the direction of boat motion upon impactwith an object in the water.

Another object is to provide a Pitot assembly including a mountingbracket attachable to a boat transom, and a Pitot tube assembly mountedon the bracket and extending downwardly and rearwardly therefrom, thePitot tube assembly including a forwardly disposed portion in the formof a knife-like edge adapted to glide smoothly through the water andshed weeds or the like due to the smooth inclined surfaces. The tubeassembly is formed with a longitudinally disposed passage terrninatingat the lower end of the assembly in a forwardly disposed openingapproximately normal to the direction of travel and somewhat shelteredto obviate the need for wire guards or the like which might upset waterflow to the Pitot tube.

Other objects and advantages will become readily apparent from thefollowing detailed description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a side elevational view, partly broken away, of a Pitotassembly embodying the principles of the present invention;

FIG. 2 is a right end elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a sectional view taken at about the line 4-4 of FIG. 1;

FIG. 5 is a sectional view taken at about the line 5-5 of FIG. 1;

FIG. 6 is an enlarged fragmentary longitudinal sectiona'l view;

FIG. 7 is an enlarged fragmentary elevational view, similar to FIG. 1,but with parts in another position; and

FIG. 8 is an enlarged fragmentary elevational view with parts in stillanother position.

While an illustrative embodiment of the invention is shown in thedrawings and will be described in detail herein, the invention issusceptible of embodiment in 3,217,535 Patented Nov. 16, 1965 "ice manydifferent forms, and it should be understood that the present disclosureis to be considered as an exemplification of the principles of theinvention, and is not intended to limit the invention to the embodimentillustrated. The scope of the invention will be pointed out in theappended claims.

Referring now to the drawings in more detail, as illustrated, apreferred embodiment of the invention includes a mounting bracket orbase 10 in the form of a bell shaped molded plastic pedestal or the likehaving a face as at 11 adapted to abut against the rear surface of thetransom of a boat. As shown herein, the base is formed with hollowspaces as at 12 in order to reduce weight. at laterally opposite sidesof the base it is recessed as at 14, and the right ends of the recessesas viewed in FIG. 1 terminate in seats as at 15 formed with apertures oropenings 16 therethrough for receiving screws or bolts adapted to holdthe base to the boat transom.

The end of the base remote from the face 11 is formed with a boretherethrough as at 18 for housing a plunger 19 adapted for receiving atthe left end (as viewed in FIG. 1) a hinge pin 21 for mounting a Pitottube assembly 23. Plunger 19 is slidably received in bore 18, and at theright end is provided with a washer of collar as at 25 retained on theplunger by peening the end of the plunger as at 26. The collar 25provides a. seat for a coiled spring 28 received in a chamber 29 in thebase and having its opposite end seated in the base as at 30. The spring28 relatively strongly urges the plunger 19 toward the right end of thebase as viewed in FIG. 1.

Tube assembly 23, in the preferred embodiment illustrated, comprises amolded plastic body including a bifurcated hinge portion 33 includingparallel extensions 33a and 33b which embrace the adjacent end of theplunger 19. Hingle pin 21 passes through the extensions 33a and 33b,through the plunger 19, and is suitably retained in position topivotally mount the tube assembly on the plunger for movement about axis21 which extends transversely of the tube assembly. At the same time,the plunger 19 is turnable about its own longitudinal axis. The resultis that the tube assembly is resiliently pivotable to the positionillustrated in FIG. 7 and resiliently turnable to the broken lineposition illustrated in FIG. 2 and the full line position of FIG. 8,either or both occurring upon impact of the tube assembly with an objectin the water while the boat is in motion.

When the tube assembly is disposed in the normal operative positionillustrated in the drawings, end faces of the extensions 33a and 33babut against cooperating seats 35a and 35b provided on the base 10.. Atthe same time, a face 36 at the lower part of hinge portion 33 abutsagainst a seat 37 on the base 10. In FIG. 7, it will be noted that thejuncture between the face 36 and the end faces of extensions 33a and 33bis in the form of a substantially right angle shoulder including anouter corner 38a and an inner corner 3812, while the juncture betweenthe seat 37 and the seats 35a and 35b is in the form of angularlyinclined surfaces 359 inclined downwardly and toward the left from anarrow horizontal lip or shoulder 40. Cooperation of the outer corner38a with the lip 40 provides a detent means which resiliently releasablylocks the tube assembly in the normal operative position againstmovement merely by pressure exerted as a result of motion o f the boatin the water, while still permitting pivotal movement of the tubeassembly about the hinge pin 21 on impact with an object in the water.The cooperation of the outer corner 38a with the inclined surfaces 39facilitates turning movement of the Pitot assembly about the axis of theplunger 19.

Tube assembly 23 includes a thin elongate extension having a forwardlydisposed portion in the form of a knife edge adapted to slice smoothlythrough the water when the boat is in motion without disturbing the flowof Water to an inlet for picking up velocity pressure. A rearwardlydisposed portion of the extension as at 46 is tubular in form andincludes a longitudinal passage 47 therethrough. At the lower end, thepassage 47 is closed as by a plug 48, and adjacent the plug an angularlydisposed passage 49 connects with the passage 47 and terminates in aforwardly facing inlet opening in a sheltered surface 52 forming part ofan angular recess at the juncture of knife edge 45 and a lower,generally horizontally disposed edge 53. At the upper end of the tubularportion 46, there is provided an annularly beaded extension 55 ofgradually reducing diameter. The extension 55 terminates in an outletopening adapted for connection with a pressure sensitive speedometermechanism as by means of flexible tubing. The tapering diameter of theextension 55 facilitates connection of such tubing of various sizes andthe annular beads on the extension serve to retain the tubing securelyin place.

Preferably, tube assembly 63 is formed with laterally outwardlyextending reinforcing webs as at 53, which diminish in width from oneend adjacent bifurcated portion 33 toward the opposite end of theassembly, as seen in the top plan view of FIG. 3.

In order to insure shedding of weeds which may slide down knife edgeportion 45 .or otherwise encounter surface 52, this surface is inclineddownwardly and slightly rearwardly and its lateral edges as at 56 (FIG.2) are inclined downwardly and laterally inwardly. Thus, stringy weedscaught across surface 52 and urged thereagainst by motion of the boat inwater are at the same time urged or cammed down the surface to slide offand drop into the water without manual removal so that the inlet openingis not obstructed. This construction obviates the need for inclined wireguards or the like for shedding weeds which guards might upset flow tothe inlet opening.

It will be understood that the Pitot assembly or velocity pressurepickup device is adapted for mounting against the rear face of a boattransom as by means of screws or b'olts passed through the bracketapertures or openings 16. When so mounted, the tube assembly 23 isadapted to extend into water with the velocity pressure passage inletopening facing forwardly in the direction of motion to pick up velocitypressure for transmission to a marine speedometer. The tube assembly isadapted to glide smoothly through the water without disturbing the flowto the pressure pickup inlet. At the same time, the downward andrearward inclination of the tube assembly is adapted to shed weedsnicely. It is unnecessary to utilize wire guards or the like which wouldupset waterfiow to the Pitot inlet.

The tube assembly is normally resiliently releasably urged to andmaintained in the position illustrated in full lines. The tube assemblyis releasably latched or locked in the full line position by cooperationof the interfitting shoulders 38 and 40 which serve as detent means, sothat movement of the tube assembly from the position shown cannot beeffected merely by pressure exerted against the tube assembly due solelyto motion in the water. On the other hand, the tube assembly may pivotupwardly toward the position illustrated in broken lines in FIG. 1 onimpact with objects in the water, such as a floating log, to preventdamage, if such impact is su-fficient to overcome the retentive effectof the interlocking shoulders. Similarly, a glancing blow against thetube assembly may effect at once a slight upward movement to release theinterlocking shoulders and an angular turning toward the positionillustrated in broken lines in FIG. 2. Pivotal movement solely about thehinge pin 21 is opposed by the spring 28 and the spring is effectiveauto matically to return the tube assembly to normal position when theforce of impact disappears. When the tube assembly is also turned aboutthe longitudinal axis of plunger 19, one of the shoulders 33a or 33b mayengage 4- the face 37 of the mounted bracket, retaining the tubeassembly in the dislocated position. The assembly may be readilyreturned to normal position by return manual movement about the axis ofplunger 19.

We claim:

1. Pitot assembly for a marine speedometer, comprising, a mountingbracket attachable to a boat transom with its longitudinal axis parallelto the length of the boat, a Pitot tube supported on the bracket in aposition to normally extend into water, said tube having at the lowerend thereof a forwardly facing inlet opening to pick up velocitypressure and at the upper end thereof an outlet opening for connectionwith a pressure sensitive speedometer mechanism, and means mounting thePitot tube on the bracket yieldably to turn laterally about alongitudinal axis relative to the mounting bracket on striking an objectin the water when the boat is in motion.

2. The combination of claim 1, including spring means for normallyresiliently maintaining the tube in the normal position.

3. The combination of claim 1, including means mounting the Pitot tubeyieldably on the bracket for movement about a horizontal axis transverseto said first mentioned axis to yield on striking objects in the waterduring motion of the boat.

4. A combination as defined in claim 1, including cooperating means onthe mounting bracket and Pitot tube for releasably retaining the tube ina laterally turned position.

5. A velocity pressure pick-up device for a marine speedometer,comprising, a mounting bracket attachable to a boat and a Pitot body onthe bracket including a thin elongate extension having front and rearportions inclined downwardly and rearwardly from the bracket at asubstantial angle from the vertical to shed weeds while the boat is inmotion, said extension front portion having a knife-like forward edge tocut smoothly through the water, said extension having a lower end edge,means providing a rearwardly extending recess in said extension at thejuncture of said forward edge and said lower end edge defined in part bya forwardly facing surface having a sheltered forwardly facing inletopening therein, and means providing a longitudinal passage through saidextension and terminating at the lower end in said inlet opening foreffectively admitting velocity pressure.

6. A velocity pressure pick-up device as defined in claim 5, whereinsaid forwardly facing surface is inclined downwardly and slightlyrearwardly and has lateral edges inclined downwardly and laterallyinwardly, thereby to shed weeds.

7. A Pitot assembly for a marine speedometer, comprising, a mountingbracket attachable to a boat with its longitudinal axis parallel to thelength of the boat, a Pitot tube supported on the bracket in a normalposition to extend downwardly and rearwardly into water, said tubehaving at the lower end thereof a forwardly facing inlet opening to pickup velocity pressure and at the upper end thereof an outlet opening forconnection with a pressure sensitive speedometer mechanism, meansmounting the Pitot tube for yieldable pivotal movement laterally about alongitudinal axis through the mounting bracket and vertically about atransverse axis through the mounting bracket upon striking an ,object inthe water during movement of the boat, and a single spring meansnormally resiliently maintaining the tube in normal position againstturning and pivotal movement.

8. The combination of claim 7, including cooperating detent means on thetube and bracket releasably locking the tube in normal position on thebracket against movement due to pressure exerted solely by motion of thetube in the water.

9. A velocity pressure pickup device for a marine speedometer,comprising, a mounting bracket attachable to a boat transom, a Pitottube on the bracket in an operative position to normally extend intowater, said tube having a forwardly facing inlet opening at the lowerend thereof to admit velocity pressure, an outlet opening at the upperend thereof for connection with a pressure sensitive speedometermechanism, and a hinge body at the upper end thereof, a longitudinallyyieldable pivot pin support on the bracket, a pivot pin pivotallyconmeeting the pin support and the hinge body for pivotal movement ofthe latter about a transverse axis, cooperating faces on the bracket andhinge body abutting when the tube is in operative position, and springmeans acting against the bracket and support normally resilientlymaintaining the tube in operative position.

10. The combination of claim 9, and said cooperating faces includingnarrow interlocking shoulder means on the hinge body and bracketparallel to the pivot pin releasably detaining the tube against movementdue to pressure exerted solely by motion of the tube in water.

11. The combination of claim 9, the pivot pin support being turnable inthe bracket about its longitudinal axis. 20

12. A combination as defined in claim 11 including cooperating means onthe bracket and Pitot tube for releasably holding the tube in alaterally turned position when the pivot pin is turned about itslongitudinal axis.

References Cited by the Examiner UNITED STATES PATENTS LOUIS R. PRINCE,Primary Examiner.

ISAAC LISANN, ROBERT L. EVANS, LEONARD FORMAN, Examiners.

1. PILOT ASSEMBLY FOR A MARINE SPEEDOMETER, COMPRISING, A MOUNTINGBRACKET ATTACHABLE TO A BOT TRANSOM WITH ITS LONGITUDINAL AXIS PARALLELTO THE LENGTH OF THE BOAT, A PILOT TUBE SUPPORTED ON THE BRACKET IN APOSITION TO NORMALLY EXTEND INTO WATER, SAID TUBE HAVING AT THE LOWEREND THEREOF A FORWARDLY FACING INLET OPENING TO PICK UP VELOCITYPRESSURE AND AT THE UPPER END THEREOF AN OUTLET OPENING FOR CONNECTIONWITH A PRESSURE SENSITIVE SPEEDOMETER MECHANISM, AND MEANS MOUNTING THEPITOT TUBE ON THE BRACKET YIELDABLY TO TURN LATERALLY ABOUT ALONGITUDINAL AXIS RELATIVE TO THE MOUNTING BRACKET ON STRIKING AN OBJECTIN THE WATER WHEN THE BOAT IS IN MOTION.